Small sailboat Design - advice requested

[dskira]

Originally Posted by ancient kayaker

dskira: it would be a real challenge to put a head in my 10' sailboat! But then my wife is not expecting to cruise on it, just a short trip around the lake is all she'll settle for.

Come to think of it, it seems a lot of work just for that! At least I will be able to use this boat to practice the gentle art of sailing. And one should never forget the words of W. Pirrie, Titanic Designer, "Your next boat will be bigger than your last."

You are right 10' is small for a head.
I like you quote of the Titanic designer.
Cheers
Daniel

[ancient kayaker]

Well, the hull is nearly complete, the area underneath the foredeck has been painted and the foredeck can go on tomorrow. Then she will need hatch covers and rudder mounts, as well as the rudder/tiller and daggerboard. Once built I can climb in and figure out the rowing arrangements. I am fortunate to have a pool so we can get acquainted before trusting myself to the lake.

I plan to make a little cart to fit in the trunk so I can wheel her from the van to the water. I am thinking of raising the top of the transom a bit so I can put a couple of holes through it and use the oars as wheelbarrow handles.

I also have to build the (first) sail rig. It will be a leg-o-mutton type http://www.duckworksmagazine.com/04/...prit/index.cfm but with a double layered sail and 2 hollow wishbone booms, so I can open it to double the area for running downwind. The sail will wrap around the mast to provide a clean airflow due to the double sided airfoil. When running several short, loose rope loops will secure the center of the sail to the mast. It should be simple to make and sail. Currently planning to have about 42/84 sq ft (4/8 m2). I can't start the mast yet (2-piece hollow spruce) as I need a 22.5 deg chamfer bit for the router.

Naturally, at this stage I am thinking about the next boat, which will have to wait a while. No harm in dreaming though! I am wondering how a 12 ft/3.6 m dinghy with shallow vee-bottom rounded bilge design will handle. I would expect that to be rather less stable than the the flattie above but faster heeled in light airs and able to plane, perhaps easier to row as well. This time it will be my own design as I want to try out a new construction idea - yet again!

[Timothy]

If you are going to use a wrap around sail and a wishbone boom that is hinged at the forward end, it will need a choker that passes from one side of the boom though holes in both plys of the sail, and is then secured to the other side of the boom . The boom itself will have to be held up by a line between the sail plys rove through a block on the mast above the height of the choker, as with wrap around sails it is necessary to have an out haul led from the cockpit to the mast base ,up to a block near the hinge ,then along one side of the wishbone boom and back to the clew, rather than a simple snotter . The resulting downward pressure on boom is considerable and must be apposed by something other than the sail where it is holed for the chocker. If you wish the sail to open for downwind sailing then you will need another out haul on the other side of the wishbone. You will not need any other lines to secure the sail to the mast . Remember that it is imperative to slacken the out haul (hauls) before lowering sail otherwise the luff is under tension and is not free to slide down the mast.

[ancient kayaker]

Timothy: many thanks for the inputs. Here’s my rigging plan so far-

As you suggest, I will use a rope (choker) passing aft of the mast through reinforced holes in the sail plies (actually just one large oval hole) and attached to the forward ends of both booms. The booms will be held up by the sail. There will be no snotter; as with a windsurfer boom the out-haul line provide sail tension. Both sail plies will have an identical arrangement, mirror images in fact, also separate sheets.

To open the sail for downwind sailing I will haul on the mainsheet for the inner ply , which will be loose. For normal sailing with the sail plies together,

I don’t see why there would be significant downward pressure on the forward end of the boom, provided the mainsheet is attached close to the clew, but if it is excessive I can add a deadeye to support the choker.

I do see a potential problem when changing tack as the tension in the inner sail ply will increase as it wraps around the mast. It may be compensated as the choker unwraps around the mast allowing the boom to move foreward. I will see what happens in practice; some problems just have to be solved on the run.

[ancient kayaker]

Moving forward, the foredeck is on, mast holes drilled and plugs (for rowing) made. Just realized my camera has a dark spot, it's not on the boat!

The lines are quite sweet, I think, but I am starting to wish I had made the buoyancy tank sides curved instead of straight, and perhaps sloping too. Oh! well, next time ...

I will build the launching cart first so I can see where I want to put the handles then I can figure out what I want to do at the transom. I can use the oars as handles. Once the transom is finished I can start sanding! I'll add the brightwork after painting as I am sometimes a sloppy painter.

I still don't have a 22.5 deg router bit but I did a short section of the hollow mast as a practice run; is ws straight forward and turned out fairly good considering I was hand-cutting the bevels.

[Timothy]

Boat looks great! The downward pressure I was referring to only applys if you want to lead the outhaul back to the cockpit so that you can adjust the flatness of the sail while at the tiller. My boat which is larger requires that I have mechanical advantage . I have a four to one purchace along the boom rather than from the cockpit to some what alleviate the problem.

[dskira]

Originally Posted by ancient kayaker

Moving forward, the foredeck is on, mast holes drilled and plugs (for rowing) made. Just realized my camera has a dark spot, it's not on the boat!

The lines are quite sweet, I think, but I am starting to wish I had made the buoyancy tank sides curved instead of straight, and perhaps sloping too. Oh! well, next time ...

I will build the launching cart first so I can see where I want to put the handles then I can figure out what I want to do at the transom. I can use the oars as handles. Once the transom is finished I can start sanding! I'll add the brightwork after painting as I am sometimes a sloppy painter.

I still don't have a 22.5 deg router bit but I did a short section of the hollow mast as a practice run; is ws straight forward and turned out fairly good considering I was hand-cutting the bevels.

I think the buoyancy tanks look pretty fine. You did a great job and looks very pleasing as is.
Cheers
Daniel

[nukisen]

"Ancient"
Thanks for the update of your building. I must say I like it a lot.
The tanks, I dont think you have to wory about them to very much. In my eyes, it looks very pretty nice .

I am considered My little boat will not become this good looking.
But I will not make this much work on it either.

Congratulation!!
I really like this one.

Well done

[nukisen]

I saw that it looks like you will use a "Centerboard".

Or will you attach a keel in the opening?

How does this look like.
And have you already placed this one.

[Rick Willoughby]

Originally Posted by ancient kayaker

Moving forward, the foredeck is on, mast holes drilled and plugs (for rowing) made. Just realized my camera has a dark spot, it's not on the boat!

The lines are quite sweet, I think, but I am starting to wish I had made the buoyancy tank sides curved instead of straight, and perhaps sloping too. Oh! well, next time ...

....

Terry
No longer the ancient kayaker. Need a name change - ancient sailor, what about ancient mariner!

Hull looks good. Always fun anticipating the launch when it gets to this stage.

Rick W

[ancient kayaker]

Originally Posted by nukisen

I saw that it looks like you will use a "Centerboard". Or will you attach a keel in the opening? How does this look like. And have you already placed this one.

It will be a daggerboard, about 0.25 x 0.75 m, lowered vertically through the trunk which is located aft of the bulkhead, visible in several of the recent photos. It will have a Clark Y profile, made of laminated cedar with a hardwood leading edge and probably brass bound on the bottom edge. I may put some pine laminations in just for the look of it.

I have just finished making the launching trolley which fits into the daggerboard slot and converts the boat into a wheelbarrow, using the oars extended beyond the transom as handles. I was lucky today, found a cheap 0.25 m diameter pneumatic wheel. It is perfect as I have to launch across a wide beach of very soft sand. I will post a photo when that is done - it should look rather neat - but I have work to do on the transom first.

Originally Posted by Rick Willoughby

Terry
No longer the ancient kayaker. Need a name change - ancient sailor, what about ancient mariner!

Hull looks good. Always fun anticipating the launch when it gets to this stage.

Rick W

We already have an ancientmariner, and I’ll always be a kayaker, in fact I have already selected the paddle I want to be buried with! So I guess I’ll remain the ancient kayaker. Are you going to become the ancient peddlar?

I too am looking forward to the launch. I usually wet new boats in my swimming pool first, to check out trim, stability, and work out any potentially embarrassing kinks. But that doesn’t count as the launch IMHO. She will probably launch first as a rowing boat then get her sails later. I’m not sure if that’s two (or three) launches. Have I confused anyone yet?

[ancient kayaker]

Some more pics of recent progress.

1. I got lucky with a nice pneumatic wheel, very cheap and the perfect size. I mounted it on a frame that fits the daggerboard slot. It needs something to stop it falling out at inconvenient moments. It fits neatly underneath the foredeck.

2. The wheel assembly forms part of my patent wheelbarrow conversion kit, shown modelled by a shady-looking itinerant working off a gambling debt between alcoholic binges. The weight on the handles (oars) is very little and it wheels along very easily.

3. Getting the boat on the van for car-topping looks doable: the transom top edge is flat so it stays firmly on the ground while I lift the bow; the wheel is quite heavy though and I will leave it out next time. I need something to grab onto for lifting the transom.

4. I also need something to protect the van and the deck from each other. That's my neighbours slightly larger boat in the background.

The rowing arrangements have been designed and finished, but are not visible in the pics. If the itinerant is still around next week I'll stick him in the boat and take a photo.

The workshop has been reconfigured for mast-building, and I now have a nice set of router bits that are perfect for cutting the bevels, so tomorrow is official mast day.

[sharpii2]

A very good looking skiff.

I like your 'V' deck for the fore deck.

I'm quite Into the idea myself.

Congrats on a good design. Cant wait to hear how it sails.

[ancient kayaker]

The original design I got from Par; there's a drawing in post #25. I changed the taped chine construction to chine log style which I prefer, and designed the foredeck and seats/bouyancy tanks myself. A lot of the detail design is driven by the rquirements I listed in the first post, but with a lot of input from the other contributors. I think she will meet all the requirements although the jury is still out on #7 & #8.

I will bright-finish the deck, and would like to do the same for the seats but one has a water stain I am trying to remove (I glued it on upside down: my own fault). If it doesn't come out they will both have to be painted.

I started on the hollow mast today. I cut a 2 x 4 (actual 1.5 x 3.5) into 3 strips a hair over 1" thick and reglued them to form a 1 x 4.5 plank from which to cut the staves. Easier than planing down a 2 x 6 plank as I don't have a thickness planer. I am making the lower section of the 2-piece telescopic mast from 8 spruce staves with 22.5 deg bevels. I will tape them together, apply glue roll them up and bind the mast - very easy to do. The plank thickness is the width of the staves when sanded - 0.97" - so I just route the bevels and cut off a stave, then repeat ...

All was going well until I was forced to use my handheld circular saw on a left-to-right cut. It blew dust straight into my eyes. Why don't they make those things blow the dust forward? It ends up on the plank anyway. I put on safety glasses which I detest. I was already wearing ear protectors and dust mask, and the goggles immediately began to fog up. The saw guide chose this moment to start to loosen, and I couldn't see what was happening.

Safety glasses are badly designed; I wore goggles for years as a motorcyclist, never had a fogging problem. What part of working half-blind do the manufacturers think is safe?

A distracted worker is a bad worker, and I started to make mistakes after I was thrown off my rhythm, so I gave up spoiling wood for the day. Fortunately I had a 50% waste allowance.

Par mentioned the birdsmouth method to me, which I think I will try on the upper mast section just for a change. Also I think I will use clear pine for the upper section, I found the spruce dust is very irritating and I will have to scarf one or two of the staves to eliminate knots.

[bistros]

Originally Posted by ancient kayaker

Par mentioned the birdsmouth method to me, which I think I will try on the upper mast section just for a change. Also I think I will use clear pine for the upper section, I found the spruce dust is very irritating and I will have to scarf one or two of the staves to eliminate knots.

I'm going to be making a birdsmouth version real soon. I can see a very simple routing jig to cut the birdsmouth - basically construct a V-form jig at 90 degrees and bring a straight router but up through the bottom of the "V", offset so that one edge of the bit is in line with the bottom of the "V". Passing stock through the jig will cut a perfect birdsmouth as long as the depth is set right for the stave thickness.

Once the staves are cut, then you can taper the stave on a table saw.

I'm going to make my mast straight for the first two feet and then tapered down from there.

--
Bill